Fuse contact structures



June 4, 1957 F. J. KOZACKA FUSE CONTACT STRUCTURES Filed March 14, 1955 United States Patent FUSE CONTACT STRUCTURES Frederick J. Kozacka, South Hampton, N. H., assignor to The Chase-Shawmut Company, Newburyport, Mass.

Application March 14, 1955, Serial No. 494,039

8 Claims. (Cl. 290-131) The invention relates to cartridge fuses, and in particular to the arrangement of contacts on cartridge fuses.

An object of the invention is the provision of high current carrying capacity cartridge fuses having contact means which require a minimum of space.

Another object of the invention is the provision of high current carrying capacity cartridge fuses having plug contacts which do not project beyond the casing or cartridge in a direction longitudinally thereof, which can be readily secured to the terminal elements of the fuse without relatively time consuming and expensive operations, and which cooperate with contacts admitting relatively large tolerances of the plug contacts.

Still another object of the invention is the provision of cartridge fuses having shock-proof and vibration-proof current-carrying ties between the terminal elements and the contacts intended for insertion into a fuse holder or the like.

Cooperating stud-type and tulip-type contacts have performed very satisfactorily in various kinds of electrical apparatus carrying high currents.

It is, therefore, another object of the invention to provide a cartridge fuse which is associated with this type of cooperating contacts.

Another object of the invention is to provide a cartridge fuse wherein the contacts of the fuse are secured by friction, or wedge action, to the terminal elements of the fuse.

Another object of the invention is to provide a cartridge fuse which has very light terminal elements and very light and compact contacts.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation together with additional objects and advantages thereof will best be understood from the following detailed description of two preferred embodiments thereof when read in connection with the accompanying drawings in which,

Fig. 1 is a longitudinal or axial section of a fuse and contact structure embodying my invention;

Fig. 2 is an elevational end view of the structure shown in Fig. 1;

Fig. 3 is a section along 33 of Fig. 1;

Fig. 4 is a longitudinal or axial section of another fuse and fuse contact structure embodying my invention; and

Fig. 5 is an elevational end view of the structure shown in Fig. 4.

Referring now to the drawings, and particularly Figs. 1 and 2 thereof, the fuse illustrated comprises two cylindrical terminal blocks or plugs 1 which are arranged in coaxial, spaced relation. Blocks 1 are preferably made of copper and fixedly held in spaced relation by a tubular casing 2 of heat shock resistant material, preferably a synthetic-resin-glass-cloth-laminate. Casing 2 is mounted on blocks 1 under pressure, as by means of a hydraulic press, and pinned to them by means of trans verse steel pins 3. The juxtaposed surfaces of blocks 1 Patented June 4, 1957 2' A a v are each provided with a system of radial grooves 111 for receiving the ends of multiperforated ribbon-type fuse links 5. Fuse links 5 are preferably made of silver but may consist of copper, if desired. The number of fuse links 5 conductively interconnecting copper blocks 1 depends upon the required current carrying capacity and upon their geometry and may widely vary from one to a very large number, e. g. one hundred. The ends of links 1 which enter into, or engage, grooves 1a are preferably soldered to blocks 1 to minimize the resistance of the current-path formed by the fuse and l 'r losses occurring in the fuse. The space within casing 2 around links 5 is preferably filled with a suitable pulverulent arc-quenching filler 4, e. g. quartz sand from which metallic impurities have been carefully removed. Each block 1 is provided with a bore 1b extending in a radial, or in a substantially radial, direction with respect to blocks 1. Tubular pins 6 inserted into bores 1 under considerable pressure are rendered highly resilient by virtue of a slot 6a provided in each pin 6 extending in a direction longitudinallythereof. To increase the resiliency of pins 6 these pins are preferably made of Phosphor bronze, whereby spring characteristics are imparted to them tending to minimize the contact resistance at their point of engagement with bores 1b. Tubular stud-type contacts 7 are arranged parallel to contact pins 6 and are secured to the latter at 7a by brazing, or an equivalent process establishing a strong mechanical tie which has but a small electric resistance. Contacts 7 may consist of lengths of solid rod rather than of tubing. It is, however, generally desirable to form stud-type contacts 7 by short lengths of tubingbecause this provides .for

elements 1. Each contact 7 is adapted to cooperate witha tulip-type contact 8 comprising a plurality of contact segments or contact bridges surrounded by a pair of garter springs 9. Garter springs 9 firmly clamp the contact segments or contact bridges of which each tuliptype contact 8 is made up against one of the stud-type or plug-type contacts 7. Terminals 13 are each in the shape of a concave solid of revolution and are engaged by the contact segments or contact bridges of which tulip-type contacts 8 are made up. The lower garter springs 9 establish contact pressure between contact segments or bridges 8 and the solids of revolution 13. Screw threaded studs 14 enable insertion of terminals 13 in any solid conductor which is provided with a cooperating female screw thread.

It will be understood from the foregoing that contacts 7 and 8 cooperate in the fashion of, or as, disconnect contacts.

The circuit through the contact and fuse structure extends as follows:

Left terminal 13, left tulip-type contact 8, left studtype contact 7, left pin 6, left block 1, fuse links 5, right block 1, right pin 6, right stud-type contact 7, right tulip-type contact 8, right terminal 13.

In the structure shown in Figs. 1 and 2 tulip-type contacts 8 are fixed and the stud-type contacts 7 movable. While this is the preferred embodiment of the invention, the tulip-type contacts may be attached to, and jointly movable with, the, casing 2 of the fuse and the stud-type contacts may be the fixed contacts.

The embodiment of the invention shown in Figs. 4.

heavy terminal blocks 1 provided in the structure of Figs. 1 and 2 are replaced by a pair of light caps 1' of sheet metal. The open ends of caps 1' are turned toward the ends of easing 2 and the closed ends of caps 1 are arranged in juxtaposed relation. A plurality of rivets 10 extends transversely across casing 2 and caps 1 to secure caps 1' firmly to casing 2. The tubular conductors 11 project transversely across casing 2 and each connects conductively one of the two caps 1' with one of a pair of stud-type or plug-type disconnect contacts 7. Each conductor 11 rests with a shoulder 12 thereof against the lateral cylindrical side wall of one of caps 1 and each. conductor 11 is upset inrivet-like fashion at the end thereof adjacent caps 1'. Contacts 7 may be connected to pins L1 by brazing or the like. Ribbontype fuse links 5 conductively interconnect caps 1', and links 5 are surrounded by a pulverulent arc-quenching filler 4 capable of absorbing relatively large amounts of arc-generated heat. The tubular stud-type or plug-type contacts 7 of the structure of Figs. 4 and 6 are intended to cooperate with tulip-type contacts 8 of the same type as shown in Figs. 1 and 2, including garter springs 9, terminals 13, and screw threaded studs 14.

While the invention has been disclosed in accordance with the provisions -of the patent statutes, it is to be understood that various changes and modifications may be made without departing from the spirit and scope of the invention. It is desired, therefore, that the appended claims be given broadest reasonable construction permissible in the light of the prior art.

I claim as my invention:

1. A fuse comprising a substantiallytubular casing of insulating material, fuse link means arranged within said casing, a pair of cylindrical'metal blocks each conductively connected to one end ofsaid fuse link means arranged within said casing at the axially outer ends thereof, each of said pair of blocks being provided with a bore extending in substantially radial direction, a pair of disconnect contacts arranged laterally of said casing each adjacent one end thereof, and a pair of tubular conductors slotted in a direction longitudinally thereof each projecting transversely across said easing into said bore in one of said pair of blocks and each conductively connecting one of said pair of blocks to one of said pair of disconnect contacts.

2. A fuse according to claim 1 wherein said pair of tubular conductors is made of Phosphor bronze.

3. A fuse comprising a substantially tubular casing of insulating material, fuse link means arranged within said casing, a pair of cylindrical metal blocks each conductively connected to one end of said fuse link means arranged within said casing at the axially outer ends thereof, each of said pair of blocks being provided with a bore extending in substantially radial direction, a pair of stud-type contacts arranged laterally of said casing at right angles to the longitudinal axis thereof, and a pair of tubular conductors slotted in a direction longitudinally thereof each projecting transversely across said easing into said bore in one of said pair of blocks and each conductively connecting one of said pair of blocks to one of said pair of stud-type contacts.

4. In combination a fuse and a pair of cooperating tulip-type contacts; said fuse comprising a substantially tubular insulating casing having a predetermined length, a pair of metallic terminal elements plugging the ends of said casing, a plurality of rnultiperforated ribbon-type fuse links conductively interconnecting said pair of terminal elements, a pair of plug contacts having a smaller spacing than said predetermined length arranged at right angles to the axis of said casing in spaced relation to said casing and to said pair of terminal elements, and a pair of supports for said pair of plug contacts each secured to one of said pair of terminal elements and each conductively connecting one of said pair of terminal elements to one of said pair of plug contacts; said pair of cooperating tulip-type'contacts each comprising a fixed contact element, a plurality of separate contact bridges each engaging said fixed contact element and one of said pair of plug contacts, and garter spring means for establishing contact pressure between said plurality of contact bridges and said fixed contact element and for establishing contact pressure between said plurality of contact bridges and one of said pair of plug contacts.

5. In combination a fuse and a pair of cooperating tulip-type contacts; said fuse comprising a substantially tubular insulating casing having a predetermined length, a pair of massive metal blocks plugging the ends of said casing, a plurality of multiperforated ribbon-type fuse links conductively interconnecting said pair of metal blocks, a pair of plug contacts having a smaller spacing than said predetermined length arranged at right angles to the axis of said casing in spaced relation to said casing and said pair of metal blocks, and a pair of supports for said pair of plugs each attached to one of said pair of metal blocks and each conductively connecting one of said pair of metal blocks to one of said pair of plug contacts; said pair of cooperating tulip-type contacts each comprising a solid of revolution, a plurality of separate contact segments each engaging said solid of revolution and one of said pair of plug contacts, and garter spring means for establishing contact pressure between one of said pair of plug contacts and said plurality of contact segments and for establishing contact pressure between one of said pair of solids of revolution and said plurality of contact segments.

6. In combination a fuse and a pair of cooperating tulip-type contacts; said fuse comprising a substantially tubular insulating casing having a predetermined length, a pair of terminal elements plugging the ends of said casing, a plurality of angularly displaced fasteners projecting transversely through said casing into said pair of terminal elements to secure said pair of terminal elements to said casing, a plurality of rnultiperforated ribbon-type fuse links conductively interconnecting said pair of terminal elements, a pair of plug contacts having a smaller spacing than said predetermined length arranged at right angles to the axis of said casing in spaced relation to said casing and to said pair of terminal elements, and a pair of supports each for one of said pair of plug contacts each attached to one of said pair of terminal elements and each conductively connecting one of said pair of terminal elements to one of said pair of plug contacts; said pair of cooperating tulip-type contacts each comprising a fixed contact element, a plurality of separate contact bridge each engaging said fixed contact element and one of said pair of plug contacts, and a pair of spaced garter springs for establishing contact pressure between said plurality of contact bridges and said fixed contact element and for establishing contact pressure between said plurality of contact bridges and one of said pair of plug contacts.

7. In a combination as specified in claim 6 a fuse comprising a pair of terminal elements formed by a pair of caps each conductively connected to one end of said plurality of fuse links and each arranged within said casing with the open end thereof turned toward one end of said casing, said pair of caps being arranged with the closed ends thereof in juxtaposed relation, said pair of supports projecting transversely across said casing and each conductively connecting one of said pair of caps to one of said pair of plug contacts.

8. In a combination as specified in claim 6 a fuse comprising a pair of terminal elements formed by a pair of caps each conductively connected to one end of said plurality of links and each arranged within said casing with the open end thereof turned toward one end of said casing, said pair of caps being arranged with the closed ends thereof in juxtaposed relation, a plurality of rivets extendin transversely across said pair of caps to secure said pair of caps to said casing, said pair of supports 5 projecting transversely across said casing each conduc- 1,061,226 tively connecting one of said pair of caps to one of said 2,653,203 pair of plug contacts, and each of said pair of supports being upset at the end thereof adjacent said pair of caps.

References Cited in the file of this patent 5 24536 UNITED STATES PATENTS 34,054 1,028,255 Murray June 4, 1912 173,404

6 Damn May 6, 1913 Kozacka Sept. 22, 1953 FOREIGN PATENTS France Apr. 25, 1922 (Addition to No. 523,994) Denmark Jan. 19, 1925 Great Britain Jan. 5, 1922 

